Using a paring knife, trim edges of dough, leaving 1″ overhanging the edge of the pie plate.
For a single-crust pie, fold and pinch the edges of overhanging dough under the edge of the pie plate. For a double-crust pie, pinch bottom and top crusts together and fold under.
Holding thumb and index finger horizontally, pinch 1″ dough along the outside edge of the pie plate, and press the index finger of other hand into the pinched fold from the inside edge of the pie plate, forming a crimp. Repeat pinching and pressing all the way around at 1″ intervals.